1. Field of the Invention
The present invention relates to an optical device and an illumination device.
2. Description of Related Art
There is a conventional illumination device which can obtain illuminating light having high directivity via a taper rod consisting of a tapered light-guide which is disposed on a light source having an LED which emits diffused light. See, for example, Japanese Patent Publication No. 2004-94115 and Japanese Patent Publication No. 2004-93623. The taper rod must be positioned for the light source.
In the field of optical fibers, various methods for adjusting the alignment of an optical component when attaching it a light source in this manner have been proposed. See, for example, Japanese Patent Publication No. Hei 10-031138, Japanese Patent Publication No. 2000-266965, and Japanese Patent Publication No. 2002-267893.